Title:
Determining Slipping Stress of Prestressing Strands in Confined Sections
Author(s):
Mohamed K. ElBatanouny and Paul H. Ziehl
Publication:
Structural Journal
Volume:
109
Issue:
6
Appears on pages(s):
767-776
Keywords:
confining stress; development length; moment capacity; slipping
DOI:
10.14359/51684120
Date:
11/1/2012
Abstract:
Development length and slipping stress of prestressing strands subjected to confining stress is not well-quantified and the appropriateness of the ACI 318-11 equation under such conditions can be questioned. In 1992, a test was performed on nineteen 14 in. (356 mm) square prestressed concrete piles with a clamping force applied during testing under lateral load. The findings indicated that the ACI 318-11 equation for development length of prestressing strands may not be suitable when used for sections subjected to confining stress. In this study, a modified equation that accounts for the effect of concrete confinement is discussed and compared to the published 1992 results and the ACI 318-11 equation. The moment strength of the sections is also compared using moment-curvature analysis by comparing three different slipping values: 1) those obtained from experimental results; 2) the ACI 318-11 equation; and 3) the modified equation.